code: def test_wiener_index_of_directed_graph():
      G = nx.complete_graph(3)
      H = nx.DiGraph(G)
      assert (2 * nx.wiener_index(G)) == nx.wiener_index(H)
  
file_path: networkx/networkx/algorithms/tests/test_wiener.py
imports: import networkx
label_desc: Use image node_id 2 for calling a global function with example usage: test_wiener_index_of_directed_graph() without return types